Abstract: An apparatus including first and second reservation stations. The first reservation station dispatches a load micro instruction, and indicates on a hold bus if the load micro instruction is a specified load micro instruction directed to retrieve an operand from a prescribed resource other than on-core cache memory. The second reservation station is coupled to the hold bus, and dispatches one or more younger micro instructions therein that depend on the load micro instruction for execution after a number of clock cycles following dispatch of the first load micro instruction, and if it is indicated on the hold bus that the load micro instruction is the specified load micro instruction, the second reservation station is configured to stall dispatch of the one or more younger micro instructions until the load micro instruction has retrieved the operand.

Abstract: An instruction translator receives a conditional load/store instruction that specifies a condition, destination/data register, base register, offset source, and memory addressing mode. The instruction instructs the microprocessor to load data from a memory location into the destination register (conditional load) or store data to the memory location from the data register (conditional store) only if the condition flags satisfy the condition. The offset source specifies whether the offset is an immediate value or a value in an offset register. The addressing mode specifies whether the base register is updated when the condition flags satisfy the condition. The instruction translator translates the conditional load instruction into a number of microinstructions, which varies as a function of the offset source, addressing mode, and whether the conditional instruction is a conditional load or store instruction.

Abstract: A processor performs out-of-order execution of a first instruction and a second instruction after the first instruction in program order, the first instruction includes source and destination indicators, the source indicator specifies a source of data, the destination indicator specifies a destination of the data, the first instruction instructs the processor to move the data from the source to the destination, the second instruction specifies a source indicator that specifies a source of data. A rename unit updates the second instruction source indicator with the first instruction source indicator if there are no intervening instructions that write to the source or to the destination of the first instruction and the second instruction source indicator matches the first instruction destination indicator.

Abstract: A microprocessor having performs an architectural instruction that instructs it to perform an operation on first and second source operands to generate a result and to write the result to a destination register only if its architectural condition flags satisfy a condition specified in the architectural instruction. A hardware instruction translator translates the instruction into first and second microinstructions. To execute the first microinstruction, an execution pipeline performs the operation on the source operands to generate the result. To execute the second microinstruction, it writes the destination register with the result generated by the first microinstruction if the architectural condition flags satisfy the condition, and writes the destination register with the current value of the destination register if the architectural condition flags do not satisfy the condition.

Abstract: An architectural instruction instructs a microprocessor to perform an operation on first and second source operands to generate a result and to write the result to a destination register only if architectural condition flags satisfy a condition specified in the architectural instruction. A hardware instruction translator translates the architectural instruction into first and second microinstructions. To execute the first microinstruction, an execution pipeline performs the operation on the source operands to generate the result, determines whether the architectural condition flags satisfy the condition, and updates a non-architectural indicator to indicate whether the architectural condition flags satisfy the condition.

Abstract: A pipelined out-of-order execution in-order retire microprocessor includes a branch predictor that predicts a target address of a branch instruction, a fetch unit that fetches instructions at the predicted target address, and an execution unit that: resolves a target address of the branch instruction and detects that the predicted and resolved target addresses are different; determines whether there is an unretired instruction that must be corrected and that is older in program order than the branch instruction, in response to detecting that the predicted and resolved target addresses are different; execute the branch instruction by flushing instructions fetched at the predicted target address and causing the fetch unit to fetch from the resolved target address, if there is not an unretired instruction that must be corrected and that is older in program order than the branch instruction; and otherwise, refrain from executing the branch instruction.

Abstract: A microprocessor includes a hardware instruction translator that translates an architectural instruction into first and second microinstructions. To execute the first microinstruction, an execution pipeline performs the shift operation on the first source operand to generate the first result and a carry flag value and updates a non-architectural carry flag with the generated carry flag value. To execute the second microinstruction, it performs the second operation on the first result and the second operand to generate the second result and new condition flag values based on the second result. If a architectural condition flags satisfy the condition, it updates the architectural carry flag with the non-architectural carry flag value and updates at least one of the other architectural condition flags with the corresponding generated new condition flag values; otherwise, it updates the architectural condition flags with the current value of the architectural condition flags.

Abstract: An out-of-order execution microprocessor executes an architectural segment register-loading instruction that instructs the microprocessor to load a new value into an architectural segment register of the microprocessor. A comparator compares the new value specified by the architectural segment register-loading instruction with a current contents of the architectural segment register. A control unit causes to be re-executed using the new value all instructions in the microprocessor that used the current architectural segment register contents as a source operand and that are newer in program order than the architectural segment register-loading instruction whenever the comparator indicates the new value does not equal the current contents.

Abstract: An instruction translator receives a conditional load/store instruction that specifies a condition, destination/data register, base register, offset source, and memory addressing mode. The instruction instructs the microprocessor to load data from a memory location into the destination register (conditional load) or store data to the memory location from the data register (conditional store) only if the condition flags satisfy the condition. The offset source specifies whether the offset is an immediate value or a value in an offset register. The addressing mode specifies whether the base register is updated when the condition flags satisfy the condition. The instruction translator translates the conditional load instruction into a number of microinstructions, which varies as a function of the offset source, addressing mode, and whether the conditional instruction is a conditional load or store instruction.

Abstract: An instruction translator translates a conditional store instruction (specifying data register, base register, and offset register of the register file) into at least two microinstructions. An out-of-order execution pipeline executes the microinstructions. To execute a first microinstruction, an execution unit receives a base value and an offset from the register file and generates a first result as a function of the base value and offset. The first result specifies the memory location address. To execute a second microinstruction, an execution unit receives the first result and writes the first result to an allocated entry in the store queue if the condition flags satisfy the condition (the store queue subsequently writes the data to the memory location specified by the address), and otherwise kills the allocated store queue entry so that the store queue does not write the data to the memory location specified by the address.

Abstract: A microprocessor instruction translator translates a conditional load instruction into at least two microinstructions. An out-of-order execution pipeline executes the microinstructions. To execute a first microinstruction, an execution unit receives source operands from the source registers of a register file and responsively generates a first result using the source operands. To execute a second the microinstruction, an execution unit receives a previous value of the destination register and the first result and responsively reads data from a memory location specified by the first result and provides a second result that is the data if a condition is satisfied and that is the previous destination register value if not. The previous value of the destination register comprises a result produced by execution of a microinstruction that is the most recent in-order previous writer of the destination register with respect to the second microinstruction.

Abstract: A microprocessor includes a plurality of execution units configured to receive instructions and operands thereof and to execute the instructions. An instruction scheduler issues the instructions to the execution units and selects sources of the instruction operands. At least one of the execution units detects one of the operands of one of the instructions is a denormal operand, generates an indication that the instruction needs to be replayed in response to detecting the denormal operand, and provides the denormal operand to the instruction scheduler in response to detecting the denormal operand, rather than normalizing the denormal operand. The instruction scheduler normalizes the denormal operand, in response to the indication, and causes the normalized operand, rather than the denormal operand, to be provided to the execution unit when the instruction is replayed.

Abstract: An out-of-order execution microprocessor includes a register alias table configured to generate a first indicator that indicates whether an instruction is dependent upon a condition code result of a shift instruction. The microprocessor also includes a first execution unit configured to execute the shift instruction and to generate a second indicator that indicates whether a shift amount of the shift instruction is zero. The microprocessor also includes a second execution unit configured to receive the first and second indicators and to generate a replay signal to cause the instruction to be replayed if the first indicator indicates the instruction is dependent upon the condition code result of the shift instruction and a second indicator indicates the shift amount of the shift instruction is zero.

Abstract: A microprocessor having performs an architectural instruction that instructs it to perform an operation on first and second source operands to generate a result and to write the result to a destination register only if its architectural condition flags satisfy a condition specified in the architectural instruction. A hardware instruction translator translates the instruction into first and second microinstructions. To execute the first microinstruction, an execution pipeline performs the operation on the source operands to generate the result. To execute the second microinstruction, it writes the destination register with the result generated by the first microinstruction if the architectural condition flags satisfy the condition, and writes the destination register with the current value of the destination register if the architectural condition flags do not satisfy the condition.

Abstract: An architectural instruction instructs a microprocessor to perform an operation on first and second source operands to generate a result and to write the result to a destination register only if architectural condition flags satisfy a condition specified in the architectural instruction. A hardware instruction translator translates the architectural instruction into first and second microinstructions. To execute the first microinstruction, an execution pipeline performs the operation on the source operands to generate the result, determines whether the architectural condition flags satisfy the condition, and updates a non-architectural indicator to indicate whether the architectural condition flags satisfy the condition.

Abstract: A microprocessor includes a hardware instruction translator that translates an architectural instruction into first and second microinstructions. To execute the first microinstruction, an execution pipeline performs the shift operation on the first source operand to generate the first result and a carry flag value and updates a non-architectural carry flag with the generated carry flag value. To execute the second microinstruction, it performs the second operation on the first result and the second operand to generate the second result and new condition flag values based on the second result. If a architectural condition flags satisfy the condition, it updates the architectural carry flag with the non-architectural carry flag value and updates at least one of the other architectural condition flags with the corresponding generated new condition flag values; otherwise, it updates the architectural condition flags with the current value of the architectural condition flags.

Abstract: A microprocessor includes an instruction translator that translates PUSHF, POP, and MOVSB x86 macroinstructions into multiple microinstructions that include a fused store microinstruction. For PUSHF, first and second microinstructions moves the x86 EFLAGS register into and mask off bits in a temporary register, and the fused store microinstruction stores it to a memory location. For POP, a first microinstruction loads a first memory location value into a temporary register and the fused store microinstruction stores it to the second memory location. For MOVSB, the first microinstruction loads a first memory location operand into a temporary register and the fused store microinstruction stores it to a second memory location. A reorder buffer receives the fused store microinstruction into exactly one entry.

Abstract: A microprocessor for improving out-of-order superscalar execution unit utilization with a relatively small in-order instruction retirement buffer. A plurality of execution units each calculate an instruction result. The instruction is either an excepting type instruction or a non-excepting type instruction. The excepting type instruction is capable of causing the microprocessor to take an exception after being issued to the execution unit, wherein the non-excepting type instruction is incapable of causing the microprocessor to take an exception after being issued. A retire unit makes a determination that an instruction is the oldest instruction in the microprocessor and that the instruction is ready to update the architectural state of the microprocessor with its result.

Abstract: A microprocessor instruction translator translates a macroinstruction into three microinstructions to perform a read/modify/write operation on a memory operand. A first microinstruction instructs the microprocessor to calculate a source address and to load the memory operand into the microprocessor from memory at the source address and to calculate a destination address. The second microinstruction instructs the microprocessor to perform an arithmetic or logical operation on the loaded memory operand to generate a result. The third microinstruction instructs the microprocessor to write the result to memory at the destination address calculated by the first microinstruction. A first execution unit receives the first microinstruction and responsively calculates the source address and loads the memory operand into the microprocessor from memory at the source address. A second execution unit also receives the first microinstruction and calculates the destination address.

Abstract: A microprocessor includes an architectural register and a non-architectural register, each having a plurality of condition code flags. A first instruction of the microarchitectural instruction set of the microprocessor instructs the microprocessor to update the plurality of condition code flags based on a result of the first instruction. The first instruction includes a field for indicating whether to update the plurality of condition code flags of the architectural or non-architectural register. A second instruction of the microarchitectural instruction set instructs the microprocessor to conditionally perform an operation based on one of the plurality of condition code flags. The second instruction includes a field for indicating whether to use the one of the plurality of condition code flags of the architectural or non-architectural register to determine whether to perform the operation.